Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
Hyers-Ulam-Rassias stability of a composite
functional equation in various normed spaces
383
403
EN
H.
Azadi Kenary
Yasouj University
azadi@mail.yu.ac.ir
In this paper, we prove the generalized Hyers-Ulam(or Hyers-Ulam-Rassias ) stability of the following composite functional equation f(f(x)-f(y))=f(x+y)+f(x-y)-f(x)-f(y) in various normed spaces.
Generalized Hyers-Ulam stability,random normed space,non-Archimedean normed spaces,fixed point method
http://bims.iranjournals.ir/article_418.html
http://bims.iranjournals.ir/article_418_aed1e9f7f9878d1f0b43d5533e3a8583.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
A note on superspecial and maximal curves
405
413
EN
A.
Kazemifard
Shahrekord University
kazemifard.ahmad@stu.sku.ac.ir
A.
R.
Naghipour
Shahrekord University
naghipour@stu.ac.ir
S.
Tafazolian
Institute for Advanced Studies in Basic Sciences
tafazolian@gmail.com
In this note we review a simple criterion, due to Ekedahl, for superspecial curves defined over finite fields.Using this we generalize and give some simple proofs for some well-known superspecial curves.
Cartier operator,Supersingular curves,finite fields,maximal curves
http://bims.iranjournals.ir/article_419.html
http://bims.iranjournals.ir/article_419_6a4faa2252a2fb3c19cfbeaa4eca5fa5.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
Contact CR-Warped product submanifolds in Kenmotsu space forms
415
429
EN
M.
Atceken
Gaziosmanpasa University, Faculty of Arts and Sciences, Department of Mathematics, 60250 Tokat/TURKEY
mehmet.atceken@gop.edu.tr
Abstract: In the present paper, we give a necessary and sufficient condition for contact CR-warped product to be contact CR-product in Kenmotsu space forms.
Kenmotsu space form,Contact CR-warped product,Contact CR-product
http://bims.iranjournals.ir/article_420.html
http://bims.iranjournals.ir/article_420_56f4f671492858923dbce165596202a3.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
On the convergence of three-step random iterative procesess with errors
of nonself asymptotically nonexpansive random
mappings
431
453
EN
R.
A.
Rashwan
Department of Mathematics, University of Assiut, P.O.Box 71516, Assiut, Egypt
rr_rashwan54@yahoo.com
D.
Al-Baqeri
Department of
Mathematics, University
of Assiut, P.O.Box 71516, Assiut, Egypt
baqeri$_$27@yahoo.com
begin{abstract} In this paper, we prove some strong and weak convergence of three step random iterative scheme with errors to common random fixed points of three asymptotically nonexpansive nonself random mappings in a real uniformly convex separable Banach space. end{abstract}
Asymptotically nonexpansive nonself random mapping,Weak and strong convergence,Common random fixed points,Completely continuous,Opial's condition
http://bims.iranjournals.ir/article_421.html
http://bims.iranjournals.ir/article_421_aa474a911e5779057293406860aac8c4.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
Localization operators on homogeneous spaces
455
467
EN
R.
Kamyabi Gol
Ferdowsi University of Mashhad
kamyabi@ferdowsi.um.ac.ir
F.
Esmaeelzadeh
Ferdowsi University of Mashhad
esmaeelzadeh@alumni.um.ac.ir
R.
Raisi Tousi
Ferdowsi University of Mashhad
raisi@ferdowsi.um.ac.ir
Let $G$ be a locally compact group, $H$ be a compact subgroup of $G$ and $varpi$ be a representation of the homogeneous space $G/H$ on a Hilbert space $mathcal H$. For $psi in L^p(G/H), 1leq p leqinfty$, and an admissible wavelet $zeta$ for $varpi$, we define the localization operator $L_{psi,zeta} $ on $mathcal H$ and we show that it is a bounded operator. Moreover, we prove that the localization operator is in Schatten $p$-class and also it is a compact operator for $ 1leq p leqinfty$.
Homogenous space,square integrable representation,n localization operator,Schatten $p$-class operator
http://bims.iranjournals.ir/article_422.html
http://bims.iranjournals.ir/article_422_8480c0250cbcd89dcc3dc2b6983c19d5.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
On pairwise weakly Lindelof bitopological spaces
469
485
EN
A.
Kilicman
University Putra Malaysia
akilic@upm.edu.my
Z.
Salleh
University Malaysia Terengganu
zabidin@umt.edu.my
In the present paper we introduce and study the notion of pairwise weakly Lindelof bitopological spaces and obtain some results. Further, we also study the pairwise weakly Lindelof subspaces and subsets, and investigate some of their properties. It was proved that a pairwise weakly Lindelof property is not a hereditary property.
bitopological space,ij-weakly Lindelof,pairwise
weakly Lindelof,ij-weakly Lindelof relative,ij-regular open and ij-regular closed
http://bims.iranjournals.ir/article_423.html
http://bims.iranjournals.ir/article_423_9d5d1804ff1eebe8d009877fcc795014.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
On nilpotent and solvable polygroups
487
499
EN
H.
Aghabozorgi
Department of Mathematics, Yazd University, Yazd, Iran
h_aghabozorgi1@yahoo.com
M.
Jafarpour
Department of Mathematics, Vali-e-Asr University, Rafsanjan, Iran
m.j@mail.vru.ac.ir
B.
Davvaz
Yazd University
davvaz@yazduni.ac.ir
Applications of hypergroups have mainly appeared in special subclasses. One of the important subclasses is the class of polygroups. In this paper, we study the notions of nilpotent and solvable polygroups by using the notion of heart of polygroups. In particular, we give a necessary and sufficient condition between nilpotent (solvable) polygroups and fundamental groups.
(semi)hypergroup,polygroup,derived polygroup,nilpotent
http://bims.iranjournals.ir/article_424.html
http://bims.iranjournals.ir/article_424_1382aa8542282fb58e8f5814d16a8370.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
Maximum sum element orders of all proper subgroups of
PGL(2, q)
501
505
EN
S.
M.
Jafarian Amri
Zanjan University
sm_jafarian@znu.ac.ir
In this paper we show that if q is a power of a prime p , then the projective special linear group PSL(2, q) and the stabilizer of a point of the projective line have maximum sum element orders among all proper subgroups of projective general linear group PGL(2, q) for q odd and even respectively
linear groups,maximal subgroups,element order
http://bims.iranjournals.ir/article_425.html
http://bims.iranjournals.ir/article_425_131e9bcb13643b18ecd70f5a42b54a7b.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
phi-Amenable and phi-biflat Banach algebras
507
515
EN
Z.
Ghorbani
Depertment of Mathematics-University of Isfahan
ghorbani@sci.ui.ac.ir
M.
Lashkarizadeh Bami
Department of Mathematics, University of Isfahan
lashkari@sci.ui.ac.ir
In this paper we study the concept of ph-biatness ofa Banach algebra A, where ph is a continuous homomorphism on A.We prove that if ph is a continuous epimorphism on A and A hasa bounded approximate identity and A is ph- biat, then A is ph-amenable. In the case where ph is an isomorphism on A we showthat the ph- amenability of A implies its ph-biatness.
Banach algebra,ph-biat,ph-amenable
http://bims.iranjournals.ir/article_426.html
http://bims.iranjournals.ir/article_426_7cc478cf8c3e322dd9f487c878ba4cfc.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
On solubility of groups with finitely many centralizers
517
521
EN
M.
Zarrin
University of Kurdistan
zarrin78@gmail.com
For any group G, let C(G) denote the set of centralizers of G.We say that a group G has n centralizers (G is a Cn-group) if |C(G)| = n.In this note, we prove that every ﬁnite Cn-group with n ≤ 21 is soluble andthis estimate is sharp. Moreover, we prove that every ﬁnite Cn-group with|G| < 30n+1519 is non-nilpotent soluble. This result gives a partial answer to aconjecture raised by A. Ashraﬁ in 2000
centralizer,n-centralizer group,soluble group
http://bims.iranjournals.ir/article_427.html
http://bims.iranjournals.ir/article_427_8d03882cd4079696032e9bedcf5e7396.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
Completely coretractable rings
523
528
EN
J.
Zemlicka
Department of Algebra
Faculty of Mathematics and Physics, Charles University in Prague,
zemlicka@karlin.mff.cuni.cz
A module $M$ is said to be coretractable if there exists a nonzero homomorphism of every nonzero factor of $M$ into $M$. We prove that all right (left) modules over a ring are coretractable if and only if the ring is Morita equivalent to a finite product of local right and left perfect rings.
coretractable module,retractable module,Kash ring
http://bims.iranjournals.ir/article_428.html
http://bims.iranjournals.ir/article_428_5da7b8715fe169e19d3b38146e66c250.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
Asymptotic properties of the sample mean in adaptive sequential sampling with multiple selection criteria
529
557
EN
A.
Parvardeh
Academic Professor
a.parvardeh@sci.ui.ac.ir
B.
Panahbehagh
Isfahan University of Technology
bardia_p@math.iut.ac.ir
M.
Salehi
Qatar University
salehi@qu.edu.qa
J.
Brown
University of Canterbury
j.brown@math.canterbury.ac.nz
D.
Smith
U.S. Geological Survey
drsmith@usgs.gov
We extend the method of adaptive two-stage sequential sampling toinclude designs where there is more than one criteria is used indeciding on the allocation of additional sampling effort. Thesecriteria, or conditions, can be a measure of the targetpopulation, or a measure of some related population. We developMurthy estimator for the design that is unbiased estimators forthe population mean, and propose another, more efficient,estimator. We investigate asymptotic properties of this estimator.We use a simulation study to investigate design properties of themulti-criteria adaptive sequential sampling scheme and also someestimator properties under the design.
Stratified sampling,Adaptive
two-stage sequential sampling,Asymptotic properties in finite
population,Consistency,Rare population
http://bims.iranjournals.ir/article_429.html
http://bims.iranjournals.ir/article_429_0d7fda83d0d219c63685429b4eeea04c.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
Biflatness and biprojectivity of Lau product of Banach algebras
559
568
EN
A.
R.
Khoddami
Ferdowsi University of Mashhad
khoddami-alireza@yahoo.com
H.
R.
Ebrahimi Vishki
Ferdowsi University of Mashhad
vishki@ferdowsi.um.ac.ir
Amonge other things we give sufficient and necessary conditions for the Lau product of Banachalgebras to be biflat or biprojective.
bimodule map,$theta$-Lau product,Tensor product,biflat,biprojective
http://bims.iranjournals.ir/article_430.html
http://bims.iranjournals.ir/article_430_ce7376069c17575dc6d19eeb2e34a06b.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
Some results on the polynomial numerical hulls of matrices
569
578
EN
H.
R.
Afshin
Department of Mathematics, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran.
hamidrezaafshin@yahoo.com
M.
A.
Mehrjoofard
Department of Mathematics, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran.
aahaay@gmail.com
A.
Salemi
Department of Mathematics, Shahid Bahonar University of Kerman, Kerman, Iran.
salemi@uk.ac.ir
In this note we characterize polynomial numerical hulls of matrices $A in M_n$ such that$A^2$ is Hermitian. Also, we consider normal matrices $A in M_n$ whose $k^{th}$ power are semidefinite. For such matriceswe show that $V^k(A)=sigma(A)$.
polynomial numerical hull,joint numerical range,normal matrices
http://bims.iranjournals.ir/article_431.html
http://bims.iranjournals.ir/article_431_3ccef3d5fa00a8a7178d1329d9bbcfd6.pdf
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
39
3
2013
07
01
Rings in which elements are the sum of an
idempotent and a regular element
579
588
EN
N.
Ashrafi
Semnan University
ashrafi49@yahoo.com
E.
Nasibi
Semnan University
ebrahimnasibi@yahoo.com
Let R be an associative ring with unity. An element a in R is said to be r-clean if a = e+r, where e is an idempotent and r is a regular (von Neumann) element in R. If every element of R is r-clean, then R is called an r-clean ring. In this paper, we prove that the concepts of clean ring and r-clean ring are equivalent for abelian rings. Further we prove that if 0 and 1 are the only idempotents in R, then an r-clean ring is an exchange ring. Also we show that the center of an r-clean ring is not necessary r-clean, but if 0 and 1 are the only idempotents in R, then the center of an r-clean ring is r-clean. Finally we give some properties and examples of r-clean rings
clean ring,exchange ring,r-clean ring,von Neumann regular ring
http://bims.iranjournals.ir/article_432.html
http://bims.iranjournals.ir/article_432_9133bb4819dd6ac2221c6ba470843a82.pdf